Pyribencarb or methyl={2-chloro-5-[(E)-1-(6-methyl-2-pyridylmethoxyimino) ethyl]benzyl}carbamate, which is an agrochemically active component, is a known benzyl carbamate-based bactericide, which is disclosed in Patent Document 1 for the first time. Non Patent Document 1 discloses that it is characterized by having a wide range of control spectrum and exhibiting an excellent controlling effect on diseases of fruits and vegetables such as gray mold, crown rot, brown rot and the like, caused by various phytopathogenic fungi including ascomycetes.
It is known that a certain chemical substance which itself does not show an activity as an agrochemical agent may be applied, simultaneously or prior or after the application of the agrochemically active component to a useful plant such as a crop or a pest to be controlled, possibly resulting in enhanced efficacy of the agrochemically active component. The aforementioned chemical substance is called an adjuvant. In the broad sense, an adjuvant refers to an auxiliary agent in contrast to a main agent in pharmaceutics. In the field of agrochemical preparations, however, an auxiliary agent used for reinforcing the efficacy of an agrochemically active component is called an adjuvant. It is possible to achieve the desired controlling effect with a smaller amount of an agrochemically active component in combination with an adjuvant. Therefore, the use of the adjuvant meets the consumer trend towards reduced agrochemical usage. Moreover, the use of the adjuvant results in reduced cost for control and reduced environmental burden. Accordingly, the use of the adjuvant is a useful technology for application of agrochemicals.
The effectiveness of adjuvants on individual agrochemically active components is based on individual compatibility. Patent Document 2 discloses a paste-like agrochemical preparation in which pyribencarb and an adjuvant are blended, and enumerates examples of the adjuvant such as fatty acid polyhydric alcohol esters, polyalkylene oxide adducts of fatty acid polyhydric alcohol esters, polyalkylene oxide fatty acid esters, polyalkylene oxide lanolin, sorbitol lanolin derivatives, polyalkylene oxide bee wax, sorbitol be wax derivatives, polysaccharide derivatives, graft polymers of C8 or higher alcohol, polyalkylene oxide, graft polymer of polyalkylene oxide, block polymers of polyalkylene oxide, and random polymers of polyalkylene.
The agrochemical formulation described in the Patent Document 2 is a paste-like composition which is applied exclusively to trees or the like by direct manual operation or directly filled in pores drilled into trees or the like. Therefore, its application is practically limited to fruit orchards, forestry and the like in which naturally vegetation is sparse and the planting area is small scale. For application of the adjuvant technology in the case of applying pyribencarb for a field of densely-planted vegetable or a large-scale agriculture with a large planting area, it is indispensable to be adapted to mechanized modern agriculture. For the purpose, the pyribencarb has to be diluted in water for spraying process, that is, the pyribencarb has to be formulated into an agrochemical preparation in the form applicable to spraying process. Needless to say, the paste-like agrochemical preparation is a highly viscous semi-solid composition suitable for coating treatment and the like, and it is not intended to be used for spraying process and does not have dilution performance inherently. Therefore, it is difficult to prepare a uniform spray solution, so it is not suitable for application by spraying process.
Typical examples of a method of treating a combination of pyribencarb and an adjuvant may include a method of separately spraying the adjuvant before or after the treatment with the pyribencarb, a method including mixing the adjuvant in situ at the time of preparing a spray solution of the pyribencarb. The former requires multiple spraying operations, and the latter requires labor to separately prepare the pyribencarb and adjuvant and subsequently weigh them separately, etc. Thus, both of them are not labor-saving. Therefore, an adjuvant-encapsulated formulation containing pyribencarb and an adjuvant in a single composition has been desired.
As a dosage form of the agrochemical composition capable of being sprayed, solid preparations such as wettable powders and water-dispersible granules, and liquid preparations such as aqueous suspensions and emulsifiable concentrates can be contemplated. Pyribencarb may be processed into any of the aforementioned types of preparations. On the other hand, when the adjuvant contained in the agrochemical composition containing the pyribencarb is a liquid within a normal temperature range or a low melting point substance even if it is a solid, it is expected to be difficult to blend the adjuvant into a solid preparation. Considering blending of adjuvants, liquid formulation will be a probable option. Furthermore, as long as the adjuvant is a substance which is easily soluble or dispersible in water, an aqueous liquid formulation represented by an aqueous suspension is the most suitable dosage form. The aqueous suspension is a liquid agrochemical preparation in which fine particles of an agrochemically active component relatively insoluble in water are suspended in water. It is a widely used form of preparation from the following reasons: there is no dusting at the time of use and there is less concern that a user is exposed to agrochemical preparations; it is easy to weigh; it is highly safe because it does not use an organic solvent which has adverse effects on the human body and the environment and has low flash point; and the like.
However, one of the problems of the preparation containing an adjuvant is that the excellent compatibility between an agrochemically active component and an adjuvant in terms of agrochemical activity does not necessarily indicate the physicochemical compatibility between the agrochemically active component and the adjuvant. Reinforcement of efficacy of the pyribencarb by such adjuvants is an appealing phenomenon, but there is no knowledge on a pyribencarb preparation in which pyribencarb and an adjuvant are packaged in a single composition to add high performance, and it is also difficult to realize such a preparation.